Why does hyperthyroidism cause breathlessness

Abnormal heart rhythms. Several heart rhythm disturbances can result from overstimulation of the thyroid. The most common are sinus tachycardia, an abnormally fast heart rate that tops beats per minute, and atrial fibrillation, a disorganized rhythm in the heart's upper chambers.

High blood pressure. In hyperthyroidism, blood vessels relax, lowering diastolic blood pressure the second, or bottom, number in a blood pressure reading. But an excess of thyroid hormone also increases the force of the heart's contractions, leading to an increase in systolic pressure the first, or top, number.

Chest pain. Whenever the heart beats more forcefully and pumps more blood, the heart muscle needs more oxygen. If a person with hyperthyroidism also has clogged coronary arteries, they may experience the chest pain known as angina, which occurs when narrowed coronary arteries can't carry all the extra blood the heart muscle demands.

Heart failure. By forcing the heart to work harder and faster, an overactive thyroid can overtax it and cause heart failure, a condition in which the heart can't pump enough blood to meet the body's needs. For information on treating and managing hyperthyroidism and other thyroid conditions, buy Thyroid Disease , a Special Health Report from Harvard Medical School.

Some people do not have an isthmus, and instead have two separate thyroid lobes. The thyroid gland uses iodine from the foods you eat to make two main hormones:.

It is important that T3 and T4 levels are neither too high nor too low. Two glands in the brain, the hypothalamus and the pituitary communicate to maintain T3 and T4 balance. The hypothalamus produces TSH Releasing Hormone TRH that signals the pituitary to tell the thyroid gland to produce more or less of T3 and T4 by either increasing or decreasing the release of a hormone called thyroid stimulating hormone TSH. Eye problems can be anywhere from mild to extremely severe. In more mild cases, your eyes may become red and inflamed.

Or they may tear or be very sensitive to light. In severe cases, the disease can cause inflammation of the eye muscles. The muscles and tissues of the eyes may become swollen and may cause your eyes to protrude from their sockets.

This is called exophthalmos. Goiter: A goiter is an enlarged thyroid gland that can cause the front of the neck to look swollen. Measure content performance. Develop and improve products. List of Partners vendors. Maybe your heart pounds quickly and loudly, your hands shake with tremors, you feel dizzy, and it's hard to catch your breath. You break out in a sweat, gripped by a sense of fear. Or maybe you feel your heart skipping beats, racing, fluttering, or pounding.

You may not realize that what feels like a panic attack or heart palpitations can be symptoms of hyperthyroidism or autoimmune Graves' disease , both of which involve an overactive thyroid. Because your thyroid and your heart are so closely intertwined, having any sort of thyroid disease can result in heart symptoms. Your thyroid and your heart are closely linked together and what affects one can affect the other. This means that when you have a suspected or diagnosed thyroid disease, you should also be assessed for heart disease.

Conversely, if you have certain heart diseases such as atrial fibrillation, heart failure, or bradycardia slowed heart rate , you should have your thyroid function checked. Having a thyroid disorder increases your chances of developing heart disease. Studies show that for people with hypothyroidism, treatment with thyroid hormones helps reduce this risk.

Whether your thyroid is overactive hyperthyroidism or underactive hypothyroidism , the way it's functioning impacts how your heart works, which can cause some of the symptoms mentioned above, as well as others. Some patients are misdiagnosed as having panic disorder or heart problems when they're actually hyperthyroid. Once treated for their overactive thyroid, these people go on to be free of these symptoms.

A toxic multinodular goiter may also cause sporadic periods of hyperthyroidism. In turn, these episodes can be a trigger for panic attacks or cause heart palpitations. This may lead to the heart symptoms listed above. However, typically hypothyroidism doesn't cause most people to have heart symptoms because it actually creates less of a demand on your heart.

When heart signs and symptoms do occur, they may include:. A condition called dyslipidemia, which means the lipids fats in your blood are abnormal, is very common in people with hypothyroidism. Usually, most people who have hyperthyroidism will find that once they're properly treated—for example, with antithyroid medications, radioactive iodine, or surgery—their panic attack-like feelings and heart symptoms become a thing of the past.

This goes if you have hypothyroidism too since thyroid hormone replacement therapy typically resolves any heart symptoms you may have and helps your heart function properly. That said, oftentimes in addition to treating the actual thyroid disorder, a type of blood pressure medication called a beta blocker Inderal propranolol or Tenormin atenolol , for example is also prescribed for people with hyperthyroidism to ease symptoms like a fast heart rate, palpitations, and nervousness.

See the separate leaflet called Thyroid Function Tests for more information. The main aim of treatment of an overactive thyroid gland hyperthyroidism is to reduce your level of thyroxine to normal. Other problems, such as a large thyroid swelling goitre or associated eye problems, may also need treatment. Factors such as the underlying cause of the problem, your age and the size of any goitre are taken into account to decide on the best treatment plan. Antithyroid medicines can reduce the amount of thyroxine made by the overactive thyroid gland.

The most common medicine used in the UK is carbimazole. Carbimazole does not affect the thyroxine which is already made and stored but reduces further production.

Therefore, it may take weeks of treatment for your thyroxine level to come down to normal. The dose of carbimazole needed to keep the thyroxine level normal varies from person to person. A high dose is usually given initially which is then reduced as your thyroxine levels come down.

Carbimazole is usually taken for months at first. After this, in about half of cases, the condition will have settled down and the carbimazole can be stopped. If the condition flares up again some time in the future, a further course may be needed.

However, in these cases an alternative treatment for example, radioactive iodine is often recommended. In about half of cases, carbimazole needs to be continued long-term to control symptoms.

A different treatment may then be a better option if you do not want to take carbimazole long-term. Warning : carbimazole can, rarely, affect your white blood cells which fight infection. Whilst taking carbimazole, you should see a doctor urgently for a blood test if you develop any of the following:.

An alternative medication called propylthiouracil is usually given instead of carbimazole if you are pregnant.

Carbimazole is safe to take if you are breastfeeding. This involves taking a drink, or swallowing a capsule, which contains radioactive iodine. The main use of iodine in your body is to make thyroxine. Therefore, the radioactive iodine builds up in your thyroid gland.

As the radioactivity is concentrated in your thyroid gland, it destroys some thyroid tissue which reduces the amount of thyroxine that you make. The dose of radioactivity to the rest of your body is very low and is not dangerous. However, it is not suitable if you are pregnant or breastfeeding. In addition, after treatment, women should not become pregnant for at least six months and men are advised not to father children for at least four months.

Following radio-iodine treatment, you should avoid prolonged contact with others for a specified time. This may be for weeks, depending on the amount of radio-iodine you receive. The aim is to limit the exposure of radioactivity to others.

For the specified period you will be advised to take precautions such as:. This involves removing part of your thyroid gland. It may be a good option if you have a large goitre which is causing problems in your neck.

If too much thyroid tissue is removed then you will be given thyroxine tablets to keep your thyroxine level normal. It is usually a safe operation.

However, as with all operations, there is a very small risk of complications. It can be difficult for a doctor to judge just the right dose of carbimazole, or just the right amount of radio-iodine, to give in each case.

Too much treatment may make your thyroxine level go too low.